The power semiconductor device is a semiconductor device for use in high breakdown voltage/large current applications, of which low loss operation is demanded. Traditionally, power semiconductor devices built on a silicon (Si) substrate have been in the main stream. In recent years, however, power semiconductor devices built on a silicon carbide (SiC) substrate have been receiving attention, and the development of such devices has been encouraged (see Patent Document 1).
The silicon carbide (SiC) material itself has a higher dielectric breakdown voltage than silicon (Si) by one order of magnitude and therefore has such a characteristic that the breakdown voltage can be maintained even when the thickness of a depletion layer at a pn junction or Schottky junction is decreased. Thus, using SiC enables decreasing the device thickness and increasing the doping density. Therefore, SiC is a promising material for formation of a power semiconductor device which has low on resistance and high breakdown voltage and which is capable of low loss operation.